Headgear for patient interface

ABSTRACT

An interface includes a mask. The mask includes a frame and a seal supported by the frame. Headgear is connected to the mask. The interface includes at least one of (i) an adjustment mechanism that can be set to a use length for a loop defined by the mask and the headgear; and (2) a break-fit assembly that can selectively lengthen the loop defined by the mask and the headgear and return to the use length.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference and made a part of thepresent disclosure.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to masks that cover a breathingpassage and structures used to secure the masks to the head. Moreparticularly, the present invention relates to generally non-stretchstructures that have at least one of an adjustment mechanism and aconfiguration providing a predetermined wearing length and a longerlength for donning.

2. Description of the Related Art

Obstructive sleep apnea (OSA) is a sleep condition in which the back ofthe throat relaxes so much while sleeping that it narrows the airway oreven entirely blocks the airway. With the constriction or closure of theairway, breathing can stop or become very shallow for a few seconds orlonger.

Continuous positive airway pressure (CPAP) is used to treat OSA. CPAPsends a flow of pressurized air that splints open the airway. The flowof pressurized air can be delivered to the user with an interface. Theinterface can include a mask and headgear, such as an elastic strap.

When donning the interface, the elastic strap is stretched to allow theheadgear to slide over the head of the user. When released, the elasticstrap tends to pull the interface against the face of the user.

As the pressure within the mask increases (e.g., 4 cm H₂O to 12 cm H₂O),the mask attempts to move away from the face of the user because thestrap securing the mask against the face is elastic. In some masks, whenthe force moving the mask away from the face of the user causes theelastic strap to stretch, the force exerted by the mask against the faceof the user decreases. Thus, as pressures increase, leaks can result inthose masks and, if suitably sealed at higher pressures (e.g., 12 cmH₂O), the elasticity of the strap causes undesirably high pressures tobe exerted against the face of the user at lower treatment pressures(e.g., 4 cm H₂O).

SUMMARY OF THE INVENTION

An object of the present invention is to provide an interface which willat least provide the industry and users with useful choice.

Some aspects of the present invention relate to headgear for use with aninterface where the headgear is generally inelastic. Generally inelasticheadgear is believed by the inventors to be superior to elastic headgearwhen used with pressures that vary dramatically over a treatmentsession, for example. However, generally inelastic headgear can bedifficult to fit and use. For example, with generally inelasticheadgear, there is a need for decoupling the headgear during donning,which can be problematic when it comes to adjusting the headgear forproper fit. Decoupling also can be difficult to manage for some users.

Certain features, aspects and advantages of the present invention relateto an interface assembly for use in providing a breathing treatment. Theinterface assembly can comprise a mask. The mask comprises a frame and aseal supported by the frame. Headgear can be connected to the mask andat least one of (i) an adjustment mechanism configured to be set to ause length for a loop defined by the mask and the headgear; and (ii) abreak-fit assembly configured to selectively lengthen the loop definedby the mask and the headgear when a predetermined force has beenexceeded and return to the use length when the predetermined force hasnot been exceeded.

In some such configurations, both the adjustment mechanism and thebreak-fit assembly. In some such configurations, the adjustmentmechanism couples the headgear to the mask. In some such configurations,the adjustment mechanism is positioned on the mask. In some suchconfigurations, the adjustment mechanism is positioned on the headgear.

In some such configurations, the break-fit assembly joins the headgearand the mask. In some such configurations, the break-fit assembly joinsthe adjustment mechanism and the mask. In some such configurations, thebreak-fit assembly joins the adjustment mechanism and the headgear. Insome such configurations, the break-fit assembly is positioned on theframe of the mask. In some such configurations, the break-fit assemblyis positioned on the headgear.

In some such configurations, the break-fit assembly comprises a magneticcoupling.

In some such configurations, the break-fit assembly comprises amechanical coupling.

In some such configurations, the adjustment mechanism is positioned onthe mask. In some such configurations, the adjustment mechanismcomprises a squeeze to lock mechanism. In some such configurations, theadjustment mechanism comprises a squeeze to unlock mechanism.

In some such configurations, the break-fit assembly comprises a biasingmember. In some such configurations, the biasing member comprises anelastic sleeve. In some such configurations, the biasing membercomprises a spring.

In some such configurations, the headgear is substantially nonstretch.

Certain features, aspects and advantages of the present invention relateto a mask and headgear system comprising a mask and headgear. The maskcomprises a frame and a seal supported by the frame. The headgear can beconnected to the mask. A break-fit assembly can be configured toelongate upon the application of a force exceeding a preselected force.The mask, headgear, and break-fit assembly together define a loop thatelongates with forces that exceed the preselected force.

In some such configurations, upon application of the force exceeding thepreselected force, the resulting elongation of the loop is sufficient toallow a user to don and position the mask on the user's head and face orto allow the user to remove the interface from the user's head and face.In some such configurations, the break-fit assembly resists elongationand remains connected in general use if a force less than thepreselected force is applied.

Certain features, aspects and advantages of the present invention relateto a break-fit assembly for a mask and headgear assembly. The break-fitassembly comprises a mechanical coupling that resists elongation from afirst length to a second length until a force is applied that exceeds apredetermined force. The mechanical coupling comprising multiple partsand a stretch biasing member that connects two or more of the multipleparts.

In some such configurations, the stretch biasing member exhibits atleast one of the following: (1) elastic characteristics and (2) springcharacteristics. In some such configurations, the stretch biasing memberprovides a connection between the parts of the mechanical coupling ofthe break-fit assembly. In some such configurations, the mechanicalcoupling requires a first force to disconnect and second force toreconnect, the second force being less than the first force.

Certain features, aspects and advantages of the present invention relateto a break-fit assembly for a mask and headgear assembly. The break-fitassembly comprises a magnetic coupling that resists elongation from afirst length to a second length until a force is applied that exceeds apredetermined force. The magnetic coupling comprising multiple parts anda stretch portion.

In some such configurations, the magnetic coupling fulfills a biasingfunction for the break-fit assembly. In some such configurations, thestretch portion provides a connection between two or more parts of themagnetic coupling.

Certain features, aspects and advantages of the present invention relateto a mask and headgear system comprising a mask configured to bepositioned on a user's face and an adjustment mechanism configured toadjust the size of the headgear to accommodate different users.

In some such configurations, the headgear comprises a material that issubstantially non-elastic. In some such configurations, the headgear issubstantially non-stretch. In some such configurations, the adjustmentmechanism comprises a buckle. In some such configurations, the bucklecomprises a hook and loop fastener. In some such configurations, theadjustment mechanism comprises a reel and coil spring. In some suchconfigurations, the adjustment mechanism includes a winding mechanism, aspool connected to the winding mechanism, and a flexible material bandconfigured to be wound onto the spool.

The term “comprising” as used in the specification and claims means“consisting at least in part of”. When interpreting a statement in thisspecification and claims that includes “comprising”, features other thanthat or those prefaced by the term may also be present. Related termssuch as “comprise” and “comprises” are to be interpreted in the samemanner.

In this specification where reference has been made to patentspecifications, other external documents, or other sources ofinformation, this is generally for the purpose of providing a contextfor discussing the features of the invention. Unless specifically statedotherwise, reference to such external documents is not to be construedas an admission that such documents, or such sources of information, inany jurisdiction, are prior art, or form part of the common generalknowledge in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Various forms of the interface will be described with reference to theaccompanying drawings.

FIG. 1 is a front view of an interface that is arranged and configuredin accordance with certain features, aspects and advantages of thepresent invention.

FIG. 2 is a side view of the interface of FIG. 1.

FIG. 3 is a perspective view of another interface that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention.

FIG. 4 is a series of drawings illustrating the interface of FIG. 3being donned by a user.

FIG. 5 is a rear view of headgear that is arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention.

FIG. 6 is a perspective view of another interface that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention.

FIG. 7 is a top view of the interface of FIG. 6.

FIG. 8 includes two simplified top views of the interface of FIG. 6showing how a strap length can be temporarily increased for donning ofthe interface.

FIG. 9 is a top view and two section views of an interface that isarranged and configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 10 is a top view, two section views and a partial side view of aninterface that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention.

FIG. 11 is a top view of a break-fit assembly that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention.

FIG. 12 is an orthogonal view of a portion of the break-fit assembly ofFIG. 11 in an open state.

FIG. 13 is a top sectioned view of a break-fit assembly that is arrangedand configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 14 is an enlarged view of a portion of the break-fit assembly ofFIG. 13.

FIG. 15 is a top sectioned view of the break-fit assembly of FIG. 13.

FIG. 16 is a top sectioned view of a break-fit assembly that is arrangedand configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 17 is another top sectioned view of the break-fit assembly of FIG.16.

FIG. 18 is a top view of an interface that is arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention.

FIG. 19 is a partial view of a portion of the interface of FIG. 18showing an adjustment mechanism.

FIG. 20 is another partial view of a portion of the interface of FIG.18.

FIG. 21 is a top view of an interface having an adjustment mechanismthat is arranged and configured in accordance with certain features,aspects and advantages of the present invention.

FIG. 22 is a simplified view of a portion of the adjustment mechanism ofFIG. 21.

FIG. 23 is a simplified view of a portion of an adjustment mechanismsimilar to that of FIG. 21, which adjustment mechanism is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention.

FIG. 24 is a view of an interface having an adjustment mechanism that isarranged and configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 25 is a partial view of a portion of the interface of FIG. 24.

FIG. 26 is a sectioned view of a portion of the portion of FIG. 25.

FIG. 27 is a partial view of a portion of the interface of FIG. 24.

FIG. 28 is a partial view of a portion of the interface of FIG. 24.

FIG. 29 is a sectioned view of a portion of the portion of FIG. 28.

FIG. 30 is a schematic view of an adjustment mechanism that is arrangedand configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 31 is a schematic view of another adjustment mechanism that isarranged and configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 32 is a perspective view of an interface with an adjustmentmechanism that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention.

FIG. 33 is a schematic view of the interface of FIG. 32.

FIG. 34 is a view of a portion of the adjustment mechanism of FIG. 32.

FIG. 35 is a schematic view of an adjustment mechanism that is arrangedand configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 36 is another schematic view of the adjustment mechanism of FIG.35.

FIG. 37 is a further schematic view of the adjustment mechanism of FIG.35.

FIG. 38 is a side view of an interface using the adjustment mechanism ofFIG. 35.

FIG. 39 is a side view of another interface using the adjustmentmechanism of FIG. 35.

FIG. 40 is a schematic view of an adjustment mechanism that is arrangedand configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 41 is a schematic view of an adjustment mechanism that is arrangedand configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 42 is a schematic view of another adjustment mechanism that isarranged and configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 43 is a schematic view of an interface having the adjustmentmechanism of FIG. 42.

FIG. 44 is another schematic view of the interface of FIG. 43.

FIG. 45 is a schematic view of an adjustment mechanism that is arrangedand configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 46 is another schematic view of the adjustment mechanism of FIG.45.

FIG. 47 is a schematic view of an interface having the adjustmentmechanism of FIG. 45.

FIG. 48 is another schematic view of the interface of FIG. 47.

FIG. 49 is another schematic view of an interface having the adjustmentmechanism of FIG. 45.

FIG. 50 is a schematic view of another interface having the adjustmentmechanism of FIG. 45.

FIG. 51 is a schematic view of an adjustment mechanism that is arrangedand configured in accordance with certain features, aspects andadvantages of the present invention.

FIG. 52 is a schematic view of an interface having the adjustmentmechanism of FIG. 51.

FIG. 53 is a schematic view of a portion of the interface of FIG. 52.

FIG. 54 is a perspective view of a strap having an adjustment mechanism.

FIG. 55 is a pair of cross-sectional views of the strap of FIG. 54.

FIG. 56 is a pair of enlarged cross-sectional views of the strap of FIG.54.

FIG. 57 is a group of cross-sectional views of other strapconfigurations that are arranged and configured in accordance withcertain features, aspects and advantages of the present invention.

FIG. 58 is a pair of perspective views of further strap configurationshaving adjustment mechanisms that are arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention.

FIG. 59 is a perspective view of an interface with an adjustmentmechanism that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention.

FIG. 60 is a front view of the interface of FIG. 59.

FIG. 61 is an enlarged perspective view of a portion of the interface ofFIG. 59.

FIG. 62 is a pair of cross-sections of the portion of the interface ofFIG. 61.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An example of an interface 100 is shown in FIGS. 1 and 2. Theillustrated interface 100 comprises a seal 102 that is supported by aframe 104. A conduit 106 connects to at least one of the seal 102 andthe frame 104. The conduit 106 can supply breathing gases to a user.

With reference still to FIGS. 1 and 2, headgear 110 connects to at leastone of the seal 102 and the frame 104. In the arrangement illustrated inFIGS. 1 and 2, the headgear 110 comprises a single strap that extendsaround a head of the user. The frame 104 can comprise two mountingpoints 112 and the strap 110 comprises cooperating mounting members 114.In some configurations, the seal 102 can comprise the mounting points112. Any suitable mounting points 112 and mounting members 114 can beused. The cooperating points 112 and members 114 facilitate easyconnection and disconnection of the mounting points 112 and mountingmembers 114. In some configurations, in addition to anchoring theheadgear 110, at least one of the mounting points 112 and/or themounting members 114 comprises a suitable mechanism for adjusting alength of the headgear 110.

The illustrated headgear 110, as described above, can be a single strap110 that passes around the back of the head. To improve stability, thestrap 110 can bifurcate near the mounting members 114 such that multiplemounting points 112 and multiple mounting members 114 can be used.

To provide a consistent experience for the user at varying treatmentpressures, the headgear 110 preferably is substantially completelynonstretch. For example, the headgear 110 can be formed of a generallyinelastic material or can comprise at least one generally inelasticcomponent that extends generally from one of the mounting members 114 tothe other of the mounting members 114. In some configurations, theheadgear exhibits limited or no substantial creep. In other words, theheadgear 110 can remain substantially the same length over its usefullife; the material preferably does not shrink or stretch to asignificant degree. By way of example but without limitation, suede is amaterial that is generally inelastic and that exhibits limited or nocreep.

Surprisingly, a generally inelastic headgear assembly (e.g., headgearcapable of elastic elongation of less than about 1 percent at a force ofabout or less than about 5 newtons) has been found to improve usercomfort and seal performance over elastic headgear. The generallyinelastic headgear 110 does not elongate as a treatment pressureincreases or varies over the course of treatment. Rather, the headgearsimply reacts to oppose any forces generated by the seal during use. Assuch, when adjusted for a proper fit at high treatment pressures, theuser does not experience too tight of a fit when the pressure decreasesto a lower treatment pressure. Moreover, with the headgear adjusted andready for use, the user generally experiences limited or no preloadprior to starting a treatment pressure.

With the generally inelastic headgear 110, the headgear 110 preferablycomprises a manner of adjusting a length of the loop defined by theinterface 100 (e.g., the headgear 110 and the frame B104 in FIGS. 1 and2). Many manners of adjusting the length will be described in moredetail below. The adjustability facilitates customizing a fit of theinelastic headgear 110 to the particular physical anatomy of the user.

With the generally inelastic headgear 110, the headgear 110 preferablycomprises a break-fit assembly. The break-fit assembly, manyconfigurations of which will be described below, facilitates donning ofthe interface 100. The break-fit assembly can facilitate slight andcontrolled elongation of the loop defined by the interface 100 to allowthe loop to expand sufficiently to slide into position around the headof the user. The extra length enables the user to pull the interfaceover the maximum circumference of the head while moving the headgearinto position below and behind the maxima occipitus, for example. Insome embodiments, the break-fit assembly provides between about 0 and200 mils of expansion. This may be in one location or split over bothsides of the associated interface.

The break-fit assembly also preferably will return to the originalposition, or a use length, once the interface 100 has been properlydonned. In some configurations, the break-fit assembly will returnautomatically once the interface 100 has been donned.

The seal 102102 and the frame B104 generally define a mask in theillustrated configuration. When breathing gases are supplied through theconduit B106 to a cavity defined within the mask, a lifting force isgenerated by the mask and the mask attempts to move away from the faceof the user.

The headgear 110 opposes the lifting force. As described above, thebreak-fit assembly allows elongation of the loop defined by theinterface 100 (e.g., by temporarily increasing a length of the strap).The break-fit assembly preferably only elongates after a break-freeforce has been applied to the assembly. The break-free force is greaterthan a maximum of the lifting force (i.e., a maximum of the liftingforce generated at the highest expected treatment force). In someconfigurations, the break-free force is about 3 Newtons to about 8Newtons.

As described above, the headgear 110 also can have a manner of adjustingthe length of the loop. In some configurations, the length adjustmentrequires an adjustment force that is greater than the break-free force.In such configurations, to adjust the length, a force greater than thatrequired to operate the break-fit assembly is required. As such, theadjustment force is greater than the break-free force and the break-freeforce is greater than the maximum lifting force. The adjustment forcealso is greater than the maximum lifting force, which can beparticularly relevant if a break-fit assembly is not used.

While the above-description has been generally directed to the assemblyof FIGS. 1-2, the description of the materials and relative forcespreferably applies to any assembly in which either or both of abreak-fit assembly and an adjustment configuration have been provided.In addition, any combination of masks, break-fit assemblies andadjustment configurations described herein is possible, is specificallycontemplated and should be understood to be within the scope of thisdisclosure and certain features, aspects and advantages of thisinvention.

With reference to FIG. 3, another interface 120 is illustrated therein.The interface 120 also comprises a seal 122, a frame 124, a conduit 126and headgear 130. While the interface 100 of FIGS. 1 and 2 was a nasalinterface, the interface 120 of FIG. 3 is a full face interface. Certainfeatures, aspects and advantages of the present invention can be usedwith any style of interface, including but not limited to nasal, oral,oral-nasal, full face, or the like.

The illustrated headgear 130 comprises a break-fit assembly 132 and anadjustment mechanism 134. The break-fit assembly 132 is shown inconnection with only the lower straps but the break-fit assembly 132also could be used on any and/or all of the straps if desired. Whileboth the break-fit assembly 132 and the adjustment mechanism 134 areshown integrated into the interface, it also is possible to incorporateonly one of the break-fit assembly 132 and the adjustment mechanism 134into the interface. Moreover, any suitable break-fit assembly and/or anysuitable adjustment mechanism can be used.

The headgear 130 preferably comprises a generally inelastic portion 136,the break-fit assembly 132 to facilitate donning of the interface 120,and the adjustment mechanism 124 to allow customization of the headgear130 to the individual user. In some configurations, the headgear 130comprises Breathoprene with a nonstretch component added to it. Forexample, the material could be a three layer laminate (i.e., foam, UBL(unbroken loop) and a nonstretch layer). In some configurations, anonstretch layer can be a center layer of a five or more layer laminate:nonstretch as a central layer with foam and UBL on each side.

With reference now to FIG. 4, the interface 130 is shown being donned bya user. As shown, the break-fit assembly 132 can extend from a firstlength L1 to a second length L2, which is greater than the first lengthL1. By extending from L1 to L2, the size of the loop defined by theheadgear 130 and the frame 124 can be increased. By increasing the sizeof the loop, the loop can be sized to a desired size for normal use yetbe extensible to a second larger size for donning without upsetting theability to immediately return to the desired size for normal use.

FIG. 5 illustrates headgear 140 in which a break-fit assembly 142 isshown on another portion of the headgear relative to the configurationshown in FIG. 4. In FIG. 5, the break-fit assembly 142 is positioned ona rear portion of the headgear 140 while, in FIG. 4, the break-fitassembly 132 is positioned between the generally inelastic portion 136(seen in FIG. 3) of the headgear 130 and the frame 124. Thus, thebreak-fit assembly can be positioned between the generally inelasticportion of the headgear and the frame as in FIG. 3, for example, or theinelastic portion of the headgear can be positioned between thebreak-fit assembly and the frame. In some configurations, the break-fitassembly can be integrated into the headgear (e.g., FIGS. 3 and 5).

With reference to FIG. 5 still, the headgear 140 comprises a generallyinelastic portion 144. A coupling portion 146, several differentembodiments of which will be described in detail below, can bepositioned along a separable seam 150. The seam 150 can be temporarilyjoined together by the coupling portion 146. In other words, the seam150 is defined by two edges (shown in dashed lines) that can beseparated but, when in close proximity, the two edges are joined by thecoupling portion 146. In some configurations, the coupling portion 146comprises one or more magnets. For example, two magnets or one magnetand one magnetizable component (e.g., an iron component) can be used.

With continued reference to FIG. 5, a return component 152 can beintegrated into the headgear 140. In the illustrated configuration, thereturn component 152 can comprise an elastic material. The returncomponent 152 can span a gap that otherwise would exist between twoflaps 154 that reside to each side of the seam 150. As such, when thegap is increased by pulling the headgear 140 (see dashed lines) andseparating the flaps 154, the return component 152 can stretch to allowdonning of the headgear 140. When the headgear 140 is released, thereturn component 152 can act to restore the headgear 140 to a positionin which the flaps 154 can approach each other and the coupling portion146 can join the flaps 154 along the seam 150.

In the illustrated configuration, the return component 152 comprises anelastic layer. For example, the return component 152 can comprise one ormore portion formed of Lycra, rubber bands, and elastic knit. Theelastic layer preferably can stretch up to about 40 mm when subjected toa tensile force of about 5 N (values may differ for a larger mask, suchas a full-face mask). In some arrangements, rather than a full layer,the return component 152 can comprise strips, cords, bands or the like.

In the illustrated configuration, the coupling portion 146 comprises twocomponents that are positioned at a lower portion of the headgear 140.Such a location is desired because it is less likely to be felt whensleeping in the headgear 140. Other locations are possible. In addition,while only two components are shown, more than two components arepossible. In some configurations, the full length of the seam 150, asubstantial portion of the full length of the seam 150 or a majority ofthe full length of the seam 150 can be formed of a magnetic material orthe like such that the coupling portion 146 also can assist in pullingthe seam 150 back together.

In some configurations, the break-fit assembly can be integrated intothe frame and/or the seal. For example, with reference to FIGS. 6through 8, an interface 160 has a frame 162 that incorporates abreak-fit assembly 164. Thus, the break-fit assembly 164 shown in FIGS.6 through 8 has been integrated into the mask (e.g., the frame of themask).

With continued reference to Figure A6, the break-fit assembly 164 canhave one or more flaps 166. The flaps 166 can seat against an outersurface 170 of the frame 162. As illustrated, the flaps 166 can beconnected to the frame 162 with hinges 172. The illustrated flaps 166can be connected to the frame 162 with one or more hinges; three hinges172 are used in the illustrated interface 160. In some configurations,biasing members, such as springs or the like, can be used to provide abiasing force that will tend to return the flaps 166 to a closed orlatched position, which position is described below.

Any suitable manner of holding the flaps 166 in position relative to theouter surface 170 of the frame 162 also can be used. In the illustratedconfiguration, a magnetic coupling 174 has been used. For example, theillustrated magnetic coupling 174 comprises at least one magnet and atleast one corresponding component from a magnetic material; theillustrated configuration comprises two magnets and two correspondingcomponents from magnetic materials on each flap 166. For the coupling174 to function, each paired component comprises at least one magnet andat least one component formed of a magnetic material (e.g., a materialthat is attracted to a magnet).

With reference to FIG. 7, headgear 176 is connected to the flaps 166 inany suitable manner. The length of the flaps 166 between the hinges 170and the point at which the headgear 176 couples to the flaps 166 definesthe length by which the loop can be increased (e.g., two times thislength can be added). Thus, lengthening the distance between the hingesand the coupling point can increase the usable length for the break-fitassembly 164 (as seen in FIG. 6). In addition, while a single flap 166is shown, the flaps 166 can comprise two or more leafs that accordionover each other. Thus, multiples of the length between the hinges andthe coupling point can be attained.

With reference still to FIG. 7, the flaps 166 can open independently ofeach other. On the left side of FIG. 7, the flap 166 is opened andconnected to the headgear 176. On the right side of FIG. 7, the flap 166is shown in solid lines in the closed or latched position and is shownmoving to the opened position. As indicated by the dashed arrow, theflap 166 swings between the latched position and the open position. Bothflaps 166 are shown in the closed position on the left in FIG. 8 andboth flaps 166 are shown in the open position on the right in FIG. 8.The movement is shown in dashed lines in FIG. 8.

With reference now to FIG. 9, an interface 180 has a frame 182 andheadgear 184. A break-fit assembly 186 can be positioned between theframe 182 and the headgear 184. The headgear 184 can comprise agenerally inelastic portion 190. The generally inelastic portion 190 canextend between two break-fit assemblies. At least one break-fit assemblycan connect the generally inelastic portion 190 to the frame 182,directly (see FIG. 10) or indirectly (see FIG. 9). In the configurationof FIG. 9, two break-fit assemblies connect the generally inelasticportion 190 to the frame 182.

The break-fit assembly 186 comprises two magnetic members 192. Asdescribed above, the magnetic members 192 can include at least onemagnet or a combination of at least one magnet and at least onemagnetizable member (e.g., a ferrous material). The magnetic members 192are oriented to be attracted to each other. As such, when the magneticmembers 192 are brought within a range to allow magnetic coupling, themagnetic members 192 self-align and self-connect.

The magnetic members 192 have a range of movement relative to each otherthat results in the magnetic members 192 moving outside of the range formagnetic coupling. For example, when the magnetic members 192 movebeyond about 10 to about 20 mils apart, the magnetic coupling force isnot strong enough to draw the magnetic members 192 back together.

Accordingly, to assist with reconnection and alignment, a flexiblesheath 194 can envelop the magnetic members 192. Because the magneticmembers 192 are very forgiving with respect to alignment, the flexiblesheath 194 is sufficient to guide the magnetic members 192 back togetherand keep the magnetic members 192 generally on the same path forreconnection. The flexible sheath 194 can be any suitable elasticmaterial. In some configurations, the flexible sheath 194 can be formedfrom silicone, a stretchy plastic material, a stretchy rubber material,or a stretch textile.

The magnetic members 192 can be fixed at least axially within theflexible sheath 192. In some configurations, the magnetic members 192are fixed rotationally and/or axially within the flexible sheath 192.The magnetic members 192 can be attached to the flexible sheath 194 inany suitable manner. For example but without limitation, the magneticmembers 192 can be glued, sewn, overmolded, or the like to secure themagnetic members 192 and the flexible sheath 192 together.

The magnetic member 194 closest to the frame 182 can be attacheddirectly (see FIG. 10) or indirectly (see FIG. 9) to the frame 182. Themagnetic member furthest from the frame 182 can be attached to an end ofthe generally inelastic member 190. In some configurations, the magneticmember 194 furthest from the frame 182 can be directly connected to theend of the generally inelastic member 190, as illustrated in FIG. 9 forexample but without limitation.

In the illustrated configuration, a portion of the sheath 194 extendsalong and/or wraps around at least a portion of the inelastic member190. In some configurations, the sheath 194 extends the full distance orsubstantially the full distance from one side of the frame 182 to theother side of the frame 182. Moreover, in some configurations, thesheath 194 can be secured to at least a portion of the inelastic member190. For example, the sheath 194 can be bonded to at least a portion ofthe inelastic member 190. Other configurations also are possible. In theillustrated configurations, a distance from the laterally outermostportion of the sheath 194 to the magnetic member 192 secured to theinelastic member 190 generally will not change. However, a distance fromthe laterally innermost portion of the sheath 194 to that same magneticmember 192 will vary due to stretching of the sheath 194

As illustrated in FIG. 9, when the outer magnetic members 192 move awayfrom the inner magnetic members 192, the length of the headgear 180increases. The movement of the magnetic members 192 away from each otheris resisted of the elastic material of the sheath 194. Thus, stretchingof the sheath 194 establishes a restoration force that will act toreturn the magnetic members 192 toward each other for reconnection to aresting position. The resting position is a position where the break-fitassembly is connected by a force sufficient to withstand the forcesgenerated by the seal of the interface during normal use of the CPAPplus hose drag. Hose drag can be any force applied to the mask system bythe CPAP hose being pulled away from the user or being dragged over anysurface. In other words, the force coupling the magnetic members 192preferably is above a maximum force created by the pressurized breathinggases within the interface, which pressurized breathing gases originatefrom the CPAP blower force. For example but without limitation, at about20 cm H₂O, there is a force of about 5 N pushing the mask away from theface of the users so the magnetic members 192 preferably exert acoupling force of greater than about 5 N. In some configurations, themagnetic attraction is preferably greater than about 4 to 5 N, whichthis takes into account a relatively high treatment pressure (e.g.,about 20 cm H₂O) and a difficult to seal patient geometry.

With reference now to FIGS. 11 through 17, additional break-fitassemblies are illustrated therein. The break-fit assemblies illustratedin FIGS. 11 through 17 achieve a break-fit function through the use ofmechanical couplings rather than magnetic couplings. Each of thebreak-fit assemblies can be connected to inelastic headgear as describedabove and can be used in place of, or in combination with, any of theother break-fit assemblies described herein. As described above, thebreak-fit assemblies facilitate a temporarily enlargement of a loopdefined by the interface to ease donning; the mechanical arrangementsdescribed herein can provide an extension of between about 25 mils andabout 100 mils in some configurations. In some configurations, theextension is between about 30 mils and about 70 mils. In someconfigurations, the extension is about 50 mils. It should be noted thatthe mechanical break-fit assemblies tend to have a longer axial lengththan the magnetic break-fit assemblies do. However, the mechanicalbreak-fit assemblies offer other distinct advantages over the use ofmagnets.

With reference first to FIGS. 11 and 12, a break-fit assembly 200 has aconstruction that allows a separation of a first component and a secondcomponent at a predetermined force while facilitating rejoining of thefirst component and the second component in a mechanical manner. In theillustrated embodiment of FIGS. 11 and 12, the first component cancomprise a post 202 with a head 204 and the second component cancomprise a receptacle 206 with a resilient opening 210. The firstcomponent and the second component can be joined by a biasing member212, such as an elasticated sleeve or spring, for example but withoutlimitation. The biasing member 212 can be secured to the first componentand the second component in any suitable manner. In addition, in theillustrated configuration, the biasing member 212 overlies any gap thatwill be created when the first component and the second componentseparate. Thus, the biasing member 212 can act to guide the reconnectionof the first and second components.

The head 204 in the illustrated configuration has a gently slopingportion 214 and a more severely angled portion 216. Similarly, thereceptacle 206 has a gently sloping portion 220 and a more sharplyangled portion 222. The surfaces 214, 216, 220, 222 are but oneconfiguration of surfaces that can be used. Advantageously, theillustrated configuration using the gently sloping interfaces 214, 220facilitates a low coupling force while using the more sharply angledinterfaces 216, 222 causes a higher separation force. Accordingly, theillustrated break-fit assembly 200 will separate at a relatively higherforce than the force required by the assembly 200 to recombine. As withthe assemblies discussed above, preferably, the assembly 200 willseparate at a tensile load of about 4 N or 5 N or more.

With reference now to FIGS. 13 through 15, another break-fit assembly230 has a construction that allows a separation of a first component anda second component at a predetermined force while facilitating rejoiningof the first component and the second component in a mechanical manner.In the illustrated embodiment of FIGS. 13 through 15, the firstcomponent can comprise a post 232 with a head 234 and the secondcomponent can comprise a receptacle 236 with an opening 240. The post232 can extend through a wall that defines the receptacle 236. As such,the post 232 can slide within the receptacle 236. With the post 232sliding within the receptacle 236, alignment generally results.

A return force between the first component and the second component canbe created by a biasing member 242. In the illustrated assembly 230, thebiasing member is positioned within the second component. As shown, thebiasing member 242 is positioned within the receptacle 236. The biasingmember 242 can be a spring, for example but without limitation. Theillustrated biasing member 242 comprises a compression spring. Aretainer 244 secures the biasing member 242 over the post 232. Theretainer can be integrally formed with the post 232 or can be separatelyformed and secured thereto in any suitable manner. The biasing member242 therefore bears against a surface of the receptacle 236 and theretainer 244.

With reference to FIG. 14, the head 234 in the illustrated configurationhas a gently sloping portion 246 and a more severely angled portion 248.Similarly, the receptacle 236 has a gently sloping portion 250 and amore sharply angled portion 252. The surfaces 246, 248, 250, 252 are butone configuration of surfaces that can be used. Advantageously, theillustrated configuration using the gently sloping interfaces 246, 252facilitates rejoining at a low coupling force while using the moresharply angled interfaces 248, 250 results in separation occurring at ahigher separation force. Accordingly, the illustrated break-fit assembly230 will separate at a relatively higher force than the assembly 230will recombine. As with the assemblies discussed above, preferably, theassembly 230 will separate at a tensile load of about 4 N or 5 N ormore.

With reference now to FIGS. 16 and 17, another break-fit assembly 260has a construction that also allows a separation of a first componentand a second component at a predetermined force while facilitatingrejoining of the first component and the second component in amechanical manner. In the illustrated embodiment of FIGS. 16 and 17, thefirst component can comprise a post 262 with a head 264 and the secondcomponent can comprise a receptacle 266 with an opening 270. The post262 can extend through a wall that defines the receptacle 266. As such,the post 262 can slide within the receptacle 266. With the post 262sliding within the receptacle 266, alignment generally results.

A return force between the first component and the second component canbe created by a biasing member 272. In the illustrated assembly 270, thebiasing member overlays at least a portion of each of the first andsecond components. The biasing member 272 can be a spring or a resilientsleeve, for example but without limitation. The illustrated biasingmember 272 is a resilient fabric sleeve that generally encases the firstcomponent and the second component.

With reference to FIG. 17, the head 264 in the illustrated configurationhas a gently sloping portion 274 and a more severely angled portion 276.Similarly, the receptacle 266 has a gently sloping portion 280 and amore sharply angled portion 282. In the illustrated configuration, thegently sloping portion 280 of the second component comprises a displacedinner wall of the receptacle 266 and the more sharply angled portion 282comprises an end of that wall that forms the gently sloping portion 280.The surfaces 274, 276, 280, 282 are but one configuration of surfacesthat can be used. Advantageously, the illustrated configuration usingthe gently sloping interfaces 274, 280 facilitates a low coupling forcewhile using the more sharply angled interfaces 276, 282 causes a higherseparation force. Accordingly, the illustrated break-fit assembly 260will separate at a relatively higher force than the assembly 260 willrecombine. As with the assemblies discussed above, preferably, theassembly 260 will separate at a tensile load of about 4 N or 5 N ormore.

As introduced above, when using generally inelastic headgear, the usermay desire some form of adjustment. In some instances, the adjustmentwill occur during set-up of the device and no further adjustment will beperformed. In other instances, the user may wish to be able to adjustthe headgear as desired. Accordingly, FIGS. 3, 7, 9 through 11, and 18through 62 will be used to describe various adjustment mechanisms thatare arranged and configured in accordance with certain features, aspectsand advantages of the present invention.

With reference initially to FIG. 3, as discussed above, the illustratedinterface 120 includes an adjustment mechanism 134. In addition, FIG. 7illustrates a similar adjustment mechanism 168 and FIG. 10 alsoillustrates a similar adjustment mechanism 198. Accordingly, thefollowing description of the adjustment mechanism 134 shown in FIG. 3can apply equally to the adjustment mechanism 168 shown in FIG. 7 and/orthe adjustment mechanism 198 shown in FIG. 10.

The adjustment mechanism 134 is a simple buckle 135 with a hook and loopfastening configuration 138 formed on the inelastic portion 136 of theheadgear 130. A tab of the hook and loop fastening configuration 138 canbe passed through an opening defined within the buckle 135 and thensecured in position after being doubled back upon itself, for examplebut without limitation. Other buckle configurations also can be used,including pin-based buckles or the like.

With continued reference to FIG. 3, the headgear 130 can be connected tothe balance of the interface 120 using hooks 139 or the like. Asillustrated, the hook 139 can be connected to a mounting structureformed on or connected to at least one of the frame 124 and the seal122. Other assemblies are possible. In the configuration illustrated inFIG. 3, both the upper strap and the lower strap include the adjustmentmechanism 134.

With reference now to FIG. 9, another adjustment mechanism 187 isillustrated therein. The adjustment mechanism 187 can comprise an insert188 that includes teeth 189 and that is secured to the break-fitassembly 186. The insert 188 can be mated with an opening in the frame182. The insert 188 interlocks with a structure in the frame 182. Insome configurations, the teeth 189 of the insert 188 interlock with astructure in the frame 182. Preferably, the insert 188 is easy to moveinward into the frame 182 but significantly more difficult to retractfrom the frame 182. An adjustment force is used to adjust the headgear.In some configurations, the frame 182 may include a release button that,when depressed, facilitates withdrawal of the insert 188 from the frame182.

With reference now to FIGS. 18-20, an interface 290 comprises a frame292 and a seal 294. Headgear 296 is connected to the frame 292 in anysuitable manner. The headgear 296 can comprise a generally inelasticmember 300 and an outer cover member 302. The outer cover member 302 cancomprise an elastic sleeve. The elastic sleeve 302 can be attached tothe frame 292 in any suitable manner. The generally inelastic member 300can move substantially freely within the sleeve 302.

With reference to FIG. 19 and FIG. 20, the generally inelastic innermember 300 has a first end 304 and a second end 306. The first end 304and the second end 306 can overlap in the region of the frame 292.Movement of the ends 304, 306 changes the size of the loop defined bythe headgear 296 and the frame 292 in the illustrated configuration. Thestretch material of the elastic sleeve 302 proves a force that urges theinner generally inelastic member to a first position (e.g., the positionshown in FIG. 19); the stretch material of the elastic sleeve 302,however, allows the ends 304, 306 to slide relative to each other suchthat the loop can be expanded. Thus, during donning of the interface290, the headgear can be expanded and, when released, the elastic sleeve302 attempts to return the headgear to the starting position.

With reference again to FIG. 18, the frame 292 can comprise a lockbutton 310. While a centrally located lock button 310 is shown, two ormore lock buttons can be used. In some configurations, a separate lockbutton can be used for each of the ends 304, 306 and the lock buttonscan be disposed laterally of the center point.

In some configurations, depressing the lock button 310 can release theends 304, 306 to allow movement of one or both of the ends 304, 306. Insome configurations, depressing the lock button 310 can lock the ends304, 306 relative to each other and relative to the frame 292 such thatthe size of the loop no longer changes. If the lock button 310 requiresdepression to lock the ends 304, 306, it is possible to allow theheadgear 296 to function like an elastic headgear until the lock button310 is depressed. In some configurations, the lock button 310 operates arelease mechanism (e.g., a clothing toggle) that allows movement whendepressed and, in some configurations, the lock button 310 operates aclamping mechanism (e.g., friction brake) that reduces or eliminates thelikelihood of movement when depressed. Any suitable locking mechanismcan be used.

In the illustrated configuration, at the extremities of the ends 304,306 are stops 312, 314. The stops 312, 314 can be used to limit theamount of stretch provided by the headgear 296. For example, the stops312, 314 can be constructed such that, while the ends 304, 306 can passthrough the frame 292, the stops cannot fully pass through the frame292. In some configurations, the stops 312, 314 are configured to notenter the frame 292 at all. Other configurations also are possible.

FIGS. 21 through 23 illustrate another interface 320 having a frame 322,a seal 324 and headgear 326. The frame 322 in the illustratedconfiguration comprises an adjustment mechanism 330. FIGS. 22 and 23illustrate slightly different variations of the adjustment mechanism330, mostly relating to a biasing member.

The adjustment mechanism 330 can be connected to the headgear 326 in anysuitable manner. For example, the headgear 326 can be formed within aninelastic member and can include hooks, clasps, or other mechanicalconnection members. Moreover, in some configurations, a break-fitassembly, including but not limited to any break-fit assembly describedherein, can be interposed between the headgear 326 and the adjustmentmechanism 330.

The adjustment mechanism 330 can be positioned within a housing of theframe 322. The adjustment mechanism 330 can be positioned around aninlet that is coupled to a supply conduit (not shown). Such apositioning provides an efficient use of space and results in asymmetric configuration. With reference to FIG. 22, the adjustmentmechanism 330 is shown in a simplified view. The adjustment mechanism330 can comprise a reel disk 322 and a coil spring 334 (see FIG. 23). Insome configurations, a coil spring can be omitted. In someconfigurations, rather than the coil spring 334, such as that of FIG.22, an elastic outer member (not shown) can be used in a manner similarto that used in the configuration of FIGS. 18 through 20.

At least one extensible member 336 can be connected to the reel disk332. Two extensible members 336 are shown in FIG. 21 while a singleextensible member is shown in FIGS. 22 and 23. When a single extensiblemember 336 is used, the member 336 preferably folds back over itself inat least one location. The extensible member 336 can be a cord, string,tape, or the like, for example but without limitation. The extensiblemember 336 preferably is generally inelastic and is mounted such that itcan be unwound from and retracted back onto the reel disk 332.

The reel disk 332 can be mounted on a spool or axle (not shown) suchthat the reel disk 332 can rotate about an axis. A locking mechanism 338can be provided to secure the length of extensible member 336 that isextended from the housing. The reel disk 322 can be provided with, orconnected to a member that includes, locking structure 340, such asrecesses, teeth, or the like. A locking pin 342 can be biased, such asby a spring 344 for example but without limitation, into the lockingstructure 340. In some configurations, a locking assembly using afriction brake or the like can be used. Desirably, the locking assemblyreduces or eliminates the likelihood of further withdrawal of theextensible member. While the extensible member 336 can be retracted intothe housing following obtaining a setting in certain configurations, theextensible member 336 preferably cannot be pulled further out from thehousing once locked.

With reference to FIGS. 24-29, an interface 350 is illustrated thatincludes a frame 352, a seal 354 and headgear 356. An adjustmentmechanism 360 can be provided that connects the headgear 356 to thebalance of the interface 350. The adjustment mechanism 360 comprises awinding mechanism similar to that discussed directly above. For example,the adjustment mechanism 360 includes a thin band of material 362, suchas a cord, tape or the like, that winds onto and off of a spool 364 suchthat the band of material 362 can coil about the spool 364.

With reference to FIG. 25, the headgear 356 can be generally inelasticand can be joined to the band 362 in any suitable manner. In theillustrated configuration, the headgear 356 and the band 362 can beconnected by a shuttle member 366. Advantageously, using the shuttle 366results in the band 362 being continuously retained within the frame352. By retaining the band 362 within the frame 352, the band 362 can beformed of a very thin material yet be protected from wear and abuse.

The shuttle member is configured to move axially along at least aportion of the frame 352. Movement of the shuttle 366 toward the spool364 (e.g., to the left in FIG. 25) acts to remove slack in the headgear356 (i.e., shorten the loop) while movement of the shuttle 366 away fromthe spool 364 (e.g., to the right in FIG. 25) acts to increase slack inthe headgear 356 (i.e., lengthen the loop). Any suitable lockingmechanism can be used to secure the assembly at a desired position. Forexample, any of the following can be locked in position: the spool 364,the band 362, the shuttle 366 or the headgear 356. In someconfigurations, the spool 364 comprises a locking mechanism such asthose described above. In some configurations, the shuttle 366 can havedetent components that click from one position from the next or theshuttle 366 can move between a clamped position and a freely slidableposition (e.g., a clamped position can be created when the shuttle 366is squeezed into position on a frame component such that it clamps ontothe frame component and a freely slidable position can be created whenthe shuttle is pulled from the frame component and able to slide alongthe frame component).

In the illustrated configuration, the shuttle member 366 is positionedin a slot 370 formed within the frame 352. The slot 370 can bepositioned as desired. For example, the slot 370 can be on a surface ofthe frame 352 that faces the user, that faces away from the user, thatfaces up or that faces down. Adjacent to the slot 370 can be graduatedmarkings to help users identify a desired setting. In someconfigurations, the slot can be omitted (see, e.g., FIG. 27). In someconfigurations, the frame 352 can simply comprise an opening rather thana slot (see, e.g., FIG. 28).

As also illustrated in FIGS. 26-29, the shuttle member 366 can becaptured or connected to the frame 352 in any desired manner. Forexample, the shuttle member 366 can include recesses that receiveflanges of the frame 352. In some configurations, the frame 352 caninclude recesses that receive flanges of the shuttle member 366.Desirably, the shuttle member 366 is connected to the frame 352 in sucha manner that the shuttle member 366 can translate along at least aportion of the frame 352.

With reference now to FIGS. 30 and 31, two different adjustmentmechanisms 380 are illustrated in a schematic fashion. The mechanism 380can be positioned in a frame of the interface (e.g., in a recess withinthe frame) or in a separate housing. In some configurations, themechanism 380 can be positioned in a housing located along a portion ofthe headgear, for example but without limitation. As described above,spools have been used to remove slack or adjust a length of theheadgear. The takeup mechanisms 380 can be used to adjust the length ofthe headgear in any of the configurations described herein. Theillustrated mechanisms 380 comprise a first set of pins 382 and a secondset of pins 384. The first set of pins 382 are positioned on a firstbody 386 and the second set of pins 384 are positioned on a second body388.

By moving the first body 386 relative to the second body 388, a lengthof an extensible member 390 can be adjusted. In FIG. 30, a single member390 is shown and, in FIG. 31, two members 390 are shown with each membersecured to one of the bodies (e.g., the first body 386).

FIG. 30 illustrates a linear movement while FIG. 31 illustrates arotational movement. Advantageously, a very small relative movementbetween the first body 386 and the second body 388 can result in asignificant change in length of the extensible member 390. Increasingthe number of pins 382, 384 increases the effect on length. Reducing thenumber of pins 382, 384 reduces the effect on length.

Any suitable movement can be used. In FIG. 31, the outer body 386 can berotated while the inner body 388 remains stationary or the outer body386 can remain stationary while the inner body 388 rotates or bothbodies 386, 388 may rotate. The relative movements can be created in anysuitable manner. For example, linear movements can be controlled by alever, a button or the like, which can be connected to one or both ofthe bodies 386, 388. Rotational movements also can be control by dials,levers, buttons or the like.

With reference now to FIGS. 32 through 34, another interface 400 isillustrated that includes a frame 402, a seal 404 and headgear 406. Anadjustment mechanism 410 can be provided. With reference to FIGS. 33 and34, the adjustment mechanism 410 comprises a rack and pinion assembly.

A pinion 412 can be mounted between two racks 414. The pinion 412 andthe racks 414 can be positioned within the frame 402. The ends of theracks 414 can connect to the headgear 406 or can be integrated into theheadgear 406. In some configurations, the racks 414 connect to theheadgear 406 outside of the frame 402. In some configurations, the racks414 connect to the headgear 406 inside of the frame 402. The racks 414can be flexible enough to wrap slightly around the pinion 412 to providemore purchase between the racks 414 and the pinion 412 and bring theracks into alignment for generally symmetrical headgear attachment. Insome configurations, relief recesses 415 can be provided to increase theflexibility of the racks 414.

With reference again to FIG. 32, a ring or other input device 416 can bepositioned on a surface of the frame 402. For example but withoutlimitation, the ring 416 can be positioned on the front of the frame 402and can surround a connector through which breathing gases are suppliedto the interface 400. Rotation of the input device 416 causes rotationof the pinion 412.

The pinion 412 comprises teeth 418 and the racks 414 include cooperatingteeth 420. As the pinion 412 rotates, the teeth 418, 420 cause axialmovement of the racks 414. In this manner, the racks 414 can be used toadjust the loop. Any suitable locking mechanism can be used to lock theposition of the headgear 406, the racks 414, the pinion 412 and/or thering 416. For instance, a pin or the like can be used to inhibitrotation of the pinion 412 and/or the ring 416. In some configurations,a friction break, a clamping mechanism, a cammed break member or thelike can be used to inhibit movement of one or more of the headgear 406,the racks 414, the pinion 412 and/or the ring 416. Moreover, while notillustrated, a break-fit assembly can be used as well. For example, theinput device can have limits that are adjustable and that limit therange of rotation. In some such configurations, a coil spring or otherbiasing member can urge the input device toward the limit associatedwith the smaller headgear size. As such, the headgear can expand butthen automatically retract to the predetermined use size under theinfluence of the biasing member.

With reference now to FIGS. 35-37, a further adjustment mechanism 420 isillustrated. The adjustment mechanism 420 comprises a resilient sleeve422 and a post 424. The resilient sleeve 422 can be formed from anysuitable material. In some configurations, the resilient sleeve 422 isformed from silicone, for example but without limitation. In someconfigurations, the resilient sleeve 422 can be formed from a wovenmaterial, which material may or may not be resilient. The post 424 canbe formed from any suitable material. In some configurations, the post424 is formed from a steel roll, for example but without limitation.

The resilient sleeve 422 includes a passage 426. The passage 426 canhave an inner diameter or inner dimension that is smaller than an outerdiameter or corresponding outer dimension of the post 424. The post canbe easily inserted into the passage 426. Insertion of the post 424 intothe passage 426 causes stretching of the resilient sleeve 422. Thestretching of the sleeve 422 causes the material to become tight againstthe post 424. Any attempt to simply apply tensile forces to the twomembers causes further tightening of the interface between the sleeve422 and the post 424. See FIG. 36. As shown in FIG. 37, to release thepost 424 from the sleeve 422, an end of the sleeve 422 can bemanipulated to effectively limit the necking of the sleeve 422 whilewithdrawing the post 424. Thus, the end of the sleeve 422 can be movedaxially away from the post 424 by causing axial compression of thesleeve. Thus, the sleeve 422 and the post 424 can form a very effectiveadjustment mechanism.

With reference to FIGS. 38 and 39, these figures illustrate two ways ofintegrating the adjustment mechanism 420 into an interface 428. Asillustrated therein, the post 424 can be formed as part of the mask(FIG. 38) or as part of the headgear (FIG. 39) and the sleeve 422 can beformed as part of the headgear (FIG. 38) or as part of the mask (FIG.39). With respect to the component that is formed on the mask side, thecomponent can be integrated into the frame or the seal. In FIG. 38, thepost 424 is formed as part of a frame 430 while, in FIG. 39, the sleeve422 is formed as part of a seal 432. Moreover, as shown in FIG. 39, ascale 424 or other demarcations can be provided along a portion of thepost 424 to indicate the length of the post 424 that has been fed intothe sleeve 422. In some configurations, the sleeve 422 can includedemarcations as well or as an alternative to the demarcations 434 on thepost 424.

With reference to FIGS. 40 and 41, two further adjustment mechanisms 450are illustrated therein. As illustrated, the adjustment mechanismscomprise a sleeve 452 and a post 454. As with the configuration justdescribed, the post 454 is received within a passage 456 of the sleeve452. As illustrated in FIG. 40, the passage 456 can comprise one or moretabs 458 that resist withdrawal of the post 454 from the passage 456.For example, the tabs 458 may slant away from an opening 460 of thesleeve 452 or the tabs 458 may be sufficiently flexible and sufficientlylong that, upon insertion of the post 454 into the passage 456, the tabs458 deflect away from the opening 460. Attempts to withdraw the post 454from the passage 456 will be resisted by the tabs 458 but the tabs willnot prevent the withdrawal of the post 454 upon the application ofsufficient force. The distance between the tabs will be smaller than thediameter or width of the post 454 such that when the post is insertedthe tabs will grip on the post and be forced to bend inwards. The lengthof the tabs and their material may cause them to grip on the post anddeform, thus increasing the interference with the post and requiring agreater force to remove the post from the sleeve.

As with the embodiment above, the adjustment mechanism 450 can be formedbetween the headgear and the mask. For example, the post 454 can beconnected to, or integrally formed with, a portion of the mask while thesleeve 452 is formed with or connected to the headgear (see FIG. 40). Insome configurations, the sleeve 452 can be integrated into, or joinedto, a hook 462. As such, the sleeve 452 and the hook 462 can be used toconnect a mask and headgear together while also providing adjustability.See FIG. 41.

With reference now to FIGS. 42 through 44, an interface 470 isillustrated. The interface 470 comprises a frame 472, a seal 474 andheadgear 476. An adjustment mechanism 480 can connect the headgear 476to the balance of the interface 470. For example, as illustrated in FIG.44, the frame 472 can include a housing 482 that contains the adjustmentmechanism 480, which is shown in FIGS. 42 and 43. The adjustmentmechanism connects to the headgear 476.

FIG. 43 illustrates that the adjustment mechanism 480 can include aplurality of telescoping members 484. The telescoping members 484 aredesigned to nest one inside of another. As such, when collapsed, thetelescoping members 484 define a first length and, when extended, thetelescoping members 484 define a second length that is longer than thefirst length. This relationship is best shown by comparing the left sideof FIG. 42 and the right side of FIG. 42.

To provide for symmetrical movement of the telescoping members 484,connecting cables 486 can be used. For example, a first connecting cable486 can join an upper portion of a first member 484 to a lower portionof a third member 484 by looping over an upper portion of a secondmember 484 (see cables on upper portion of FIG. 42). Similarly, a secondconnecting cable 486 can join a lower portion of the third member 484 toan upper portion of the first member 484 by looping under a lowerportion of the second member 484 (see cables on lower portion of FIG.42). When the members 484 move, the cable or cables 486 maintainbalanced positions that result in the members moving in a synchronizedmanner.

The outermost member 484 can define an end magnet or magnetizablematerial that can be connected to, or can define, an end cap 490 oftheadjustment mechanism 480. Located at the upper portion of the thirdmember 484 can be another magnet or magnetic material that defines abase 491, which in one position is adjacent the end cap 490. The end cap490 and the base 491 may both comprise magnets, respectively, or one maycomprise a magnet while the other comprises a magnetizable material. Theend cap 490 and the base 491 are held together with a magnetic force.When adjacent to each other, the distance or length between the lowerportion of the base 491 to the upper portion of the end cap 490 isdefined as L3. If a force exceeding the magnetic force is applied in anopposing direction the one or more magnets will be forced apart todefine a distance or length of L4 where L4 is greater than L3.

The end cap 490 and the base 491 together provide the same or a similarbreak-fit function as those described in FIGS. 9 and 10. When an axialforce is applied to the end cap 490, the end cap 490 pulls away from thebase 491 thereby loosening the tension on the headgear 476, which may bebeneficial for ease of removal or adjustment. Because of the magneticforce between the end cap 490 and the base 491, the two elements maytend to be drawn back together when the force keeping them apart isremoved or reduced. Other elements of the headgear 476 may also draw thetwo elements back together. For example, a resilient member 492 (asdescribed in greater detail below) may comprise an elastic material thatwill draw the end cap 490 and the base 491 back toward each other ifseparated.

In some embodiments, the end cap 490 is secured to the upper portion ofa telescoping member 484. In FIG. 42, end cap 490 is shown as affixed tothe upper portion of the fourth telescoping member 484. Because thefourth telescoping member 484 slides into and out of the thirdtelescoping member 484, the base 491 positioned at the upper end of thethird telescoping member 484 may be configured to accommodate suchmovement. For example, in some embodiments, the base 491 comprises anannular shape that allows the fourth telescoping member 484 to slideinto and out of both the base 491 as well as the third telescopingmember 484. Such movement comes into play in the break-fit operation ofthe end cap 490 and base 491. In some embodiment, the base 491 comprisesany number of shapes having an interior opening to accommodate thefourth telescoping member 484. In some embodiments, the base 491 ispositioned to one or more sides of the slot 496 of the third telescopingmember 484. Thus, the movement of the fourth telescoping member 484 isnot impeded and the end cap 490 can still be held in place with amagnetic force.

The members 484, the connecting cables 486, the end magnet and the endcap 490 can be enclosed with a resilient member 492. Any suitableresilient member 492 can be used. In some configurations, the resilientmember 492 is a strip of material. In other applications, the resilientmember 492 forms an envelope around the members 484 and the end cap 490.As best shown in FIG. 42, the illustrated resilient member 492 resistsmovement of the end cap 490 away from the centerline CL. Moreimportantly, the resilient member applies a restorative force when themembers 484 extend outward.

Because the telescoping members 484 are nested and are slidinglyconnected and can include one or more connecting cables B486, the entireassembly can be locked into a position by locking only one of themembers 484. In other words, the connecting cables 486 operate in abalanced manner and so stopping the movement of one member 484 relativeto another member 484 causes all of the members 484 to stop. Moreparticularly, by controlling the movement at lock point 494, the entireadjustment mechanism can be controlled. For example, clamping togetherthe centermost member 484 and the adjacent member 484 will reduce oreliminate the likelihood of movement of the other members 484.

The members 484 can include slots 496. Pins 498 can extend betweenadjacent members 484 in a slot such that the members are coupledtogether. To provide the lock point 494, one of the pins 498 can extendthrough a slot 500 formed in the housing 482, as shown in FIG. 44. Otherlocking configurations also can be used. For example, multiple stops canbe provided with a pin fitting into one of the holes that define themultiple stops. Desirably, the locking configuration will lock outmovement between at least one of the members 484 and the housing 482 orwill lock out movement between at least two adjacent members 484.

With reference now to FIGS. 45 through 50, and especially to FIGS. 47and 48, an interface 510 is illustrated that has a frame 512, a seal514, headgear 516 and an adjustment mechanism 520. The adjustmentmechanism 520 can comprise a scissor mechanism, as will be described. Insome configurations, the adjustment mechanism 520 can be connected tothe frame 512. In some configurations, the adjustment mechanism 520 canbe positioned within a housing 522. In some configurations, the housing522 can be connected to the frame 512. In some configurations, thehousing 522 forms a portion of the frame 512. In some configurations,the headgear 516 is connected to the frame 512 with the adjustmentmechanism 520 contained within the housing 522.

With reference to FIG. 47, the adjustment mechanism 520 preferablycomprises a first base component 530 and a second base component 532.The first and second components 530, 532 can comprise rings in someconfigurations. The first ring 530 and the second ring 532 can bepositioned side by side with a single rotational axis extending throughthe two rings 530, 532. The first ring 530 includes two lugs 534 thatare approximately 180 degrees apart. The second ring 532 includes twolugs 536 that also are approximately 180 degrees apart.

A pair of crossing scissor arms 540 connect to the lugs 534, 536 on eachside of the rings 530, 532. The scissor arms 540 can be connected at apin joint 542. In addition, the connections between the scissor arms 540and the lugs 534, 536 can be pin joints. While one set of scissor arms540 are shown for each side of the adjustment mechanism 520, othernumbers can be used.

An end piece 544 can be connected to the scissor arms 540 with stub arms546. A first end of the stub arms can be connected to the scissor arms540 with pin joints. Similarly, a second end of the stub arms can beconnected to the end piece 544 with pin joints.

When the end piece 544 is moved relative to the first ring 530 and thesecond ring 532, the stub arms 546 and the scissor arms 540 fold andunfold while the first ring 530 and the second ring 532 rotate. Forexample, as shown in FIG. 45, when the end piece 544 is in thecontracted position, an angle α between the lugs 534 and an line thatextends through the rotational axis of the rings 530, 532 as well as thepin joints of the scissor arms 540 is greater than when the end piece544 is in the extended position. Thus, the angle α decreases as thedistance between the center axis CA and the end piece 544 increases.

The adjustment mechanism 520 includes a biasing member 548. In theillustrated arrangement, the biasing member 548 urges the end piece 544toward the center axis CA. In some configurations, the biasing member548 can be one or more strips of an elastomeric material or a springmember. In some configurations, the biasing member 548 can be anenveloping stretchable fabric or other material. Any suitable biasingmember can be used. In some configurations, the biasing member 548 alsois the housing 522. The biasing member provides a restorative force thatseeks to return the end pieces 544 to the contracted position.

With reference still to FIGS. 45 and 46, a locking component 550 can beused to secure the adjustment mechanism 520 in a desired position. Forexample, in the illustrated configuration, the rings 530, 532 cancomprise one or more recesses 552 that extend around the periphery ofthe rings 530, 532. The recesses can be in the form of teeth, forexample but without limitation. A pin 554 can engage with the recesses552 to reduce or eliminate the likelihood of rotation of the rings 530,532 when movement is not desired. In some configurations, only one ofthe first and second rings 530, 532 is secured against movement.

Of course, any other suitable locking mechanism can be used. FIG. 49illustrates a cam assembly 560. The cam assembly 560 can use a cammounted to a lever. The first and second rings 530, 532 can be squeezedtogether by the cam. As such, when the lever is moved to the lockedposition, at least one of the first and second rings 530, 532 cannotrotate. In some configurations, both of the first and second rings 530,532 cannot rotate. Another mechanism, illustrated in FIG. 50, caninclude a threaded ring assembly 562, which features a locking ring thattightens against at least one of the first and second rings 530, 532.The locking ring, when tightened, can secure at least one or both of thefirst and second rings 530, 532 from rotation.

As discussed above, the adjustment mechanisms described herein can beused with break-fit assemblies where desired. With reference to FIG. 46,an integration of an adjustment mechanism and a break-fit assembly willbe described. The adjustment mechanism has been described above. Tointegrate a break-fit assembly 570, the end piece 544 and a plate 572can be releasably coupled together. In some configurations, the endpiece 544 and the plate 572 can be magnetically coupled. In someconfigurations, at least one of the end piece 544 and the plate 572 isor includes a magnet. The magnetic coupling between the end piece 544and the plate 572 is sufficiently strong to allow the connection toremain during treatment yet sufficiently weak to allow separationbetween the end piece 544 and the plate 572 when donning the interface510. The elastic member 548 continues to stretch even beyond the fullrange of adjustment by the adjustment mechanism 520 (e.g., about anadditional 50 mils). Thus, if the adjustment mechanism 520 is locked ata position between collapsed and extended, the elastic member 548 willcontinue to stretch when the plate 572 breaks free from the end piece544 during donning of the interface 510.

While the adjustment mechanism 520 described with respect to Figures A45through A48 featured a coordinated expansion to both sides due to theinterconnecting rings 530, 532, an adjustment mechanism 580 can haveindependent movement of the two sides. For example, the adjustmentmechanism 580 shown in FIGS. 51-53 can allow adjustment of two sidesindependently of each other. As illustrated, the adjustment mechanism580 can include at least a first gear 582 and a second gear 584. Thefirst gear 582 and the second gear 584 can be engaged such that rotationof one of the gears 582, 584 results in rotation of the other one of thegears 582, 584.

A first lever arm 586 can extend away from the first gear 582 and asecond lever arm 588 can extend away from the second gear 584. The firstlever arm 586 and the first gear 582 are coupled for rotation and thesecond lever arm 588 and the second gear 584 are coupled for rotation.

A pair of crossing scissor arms 590 connect to the lever arms 586, 588.The scissor arms 590 can be connected at a pin joint 592. In addition,the connections between the scissor arms 590 and the lever arms 582, 584can be pin joints. While one set of scissor arms 590 are shown for eachside of the adjustment mechanism 580, other numbers can be used.

An end piece 594 can be connected to the scissor arms 590 with stub arms596. A first end of the stub arms 596 can be connected to the scissorarms 590 with pin joints. Similarly, a second end of the stub arms 596can be connected to the end piece 594 with pin joints.

When the end piece 594 is moved relative to the gears 582, 584, the stubarms 596 and the scissor arms 590 fold and unfold while the gears 582,584 rotate. As shown in FIG. 51, the end piece 594 can move between acontracted position (solid lines) and an extended position (dashedlines).

As shown in FIG. 52, the adjustment mechanism 580 can comprise anelastic cover 598, similar to the configurations described above. Thecover 598 encloses the mechanical assembly and applies a force thaturges the mechanism back to the contract position. Any of the biasingstructures described herein can be used. In addition, the break-fitassembly described above can be integrated in the same manner.Effectively, relative to the other scissor arms assembly describedabove, the assembly of FIGS. 51-53 exchanges the two rings for fourgears and isolates the movement of the two sides.

As described above, it is possible to use hook and loop fasteners withbuckles or the like to provide an adjustment mechanism. With referenceto FIGS. 54-58, a few assemblies that can be used in place of hook andloop fasteners are illustrated. These assemblies feature components thatcan be formed of silicone or another polymeric material. Accordingly,these features facilitate molding with either headgear or anothercomponent of the interface.

With reference to FIG. 54, a strap 610 is shown doubled back on itself.A slider 612 can be used to slide over at least a portion of the strap612. The strap 610 can include one or more rails 614. The rails 614, asshown in FIG. 55, can include a narrow rib 616 with an enlarged cap 618.When pressed together on itself, each rail 614 can deflect. Asillustrated, the enlarged cap 618 can interlock with itself to join thestrap. The slider 612, as it slides over the doubled over portion of thestrap 610, helps to cause the rails 614 to interlock. As an adjustmentmechanism, the straps 610 allow a significant length that can be usedand, because of the construction and the interlocking of the rails 614,the straps 610 will not be prone to having a free end dangling. In otherwords, the excess length is easily managed.

With reference to FIG. 57, another strap 620 is illustrated. The strap620 comprises two rails 622. Each of the rails 622 can comprise aC-shaped cap 624 that sits atop a narrower rib 626. As illustrated, whenpressed together, one of the two caps 624 will compress to fit inside ofthe other of the two caps 624. Thus, when the strap is doubled overitself and pressed together, the strap 620 doubled over portion can lockto itself in the longitudinal direction.

FIG. 57 also illustrates a second strap 630. The strap 630 comprisesfour rails 632. Two of the rails 632 each comprise a C-shaped cap 634that sits atop a narrower rib 636. Two of the rails 632 each comprise asmall head 638 that sits atop a narrower rib 640. When pressed together,the small head 638 can snap into the recess of the C-shaped cap 634.Thus, when the strap 630 is doubled over itself and pressed together,the strap 630 can lock to itself in the longitudinal direction.

FIG. 58 shows another strap 650. The strap 650 can lock to itself in atransverse direction. As illustrated, the strap 650 can comprise an end652 with a stop 654. In addition, the end 652 can include a tab 656,which can be sized to accommodate a slider member 658. The slider member658 can track along the axial direction of the strap 650.

One side of the illustrated strap 650 includes transversely extendingribs 660. The ribs 660 are shaped to enable the ribs 660 to locktogether when pressed. The other side of the illustrated strap 650 issubstantially smooth.

The slider member 658 has an opening large enough to accommodate twothicknesses of the strap 650 so long as the two thicknesses have theribs 660 interlocked. Accordingly, the tab portion 656 is generallysmooth on both sides such that, when the slider member 658 is positionedover the tab portion 656, the location of the tab portion 656 can beadjusted (see lower portion of FIG. 58). Once positioned as desired, theslider member 658 can be slid away from the stop 654. As the slidermember 658 traverses the strap 650, the ribs 660 are pressed togetherand the strap locks to itself in a transverse direction.

With reference now to FIGS. 59 through 62, an interface 700 isillustrated. The interface 700 includes a mask frame 702, a seal 704 andheadgear 706. An adjustment mechanism 710 connects the headgear 706 tothe balance of the interface 700.

In the illustrated configuration, the frame 704 comprises arms 712 thatextend laterally outward. As illustrated, the arms 712 can includerecessed grooves 714 that extend along one or both of the top andbottom.

The headgear 706 connects to a slide 720. In the illustratedconfiguration, the headgear 706 is pivotally connected to the slide 720.Other types of connections also can be used. The slide 720 can include atooth 722 that fits into each of the recessed grooves 714 of the arms712. The slide 720 should define a larger inside dimension than acorresponding outside dimension of the arm 712 such that the slide 720can be compressed toward the arm 712.

With reference to FIG. 60, the slide 720 generally is locked in positionalong the arm 712 until compressed. For example, as illustrated in FIG.60, compressing the slide 720 in the direction of the teeth (e.g.,vertically as shown) releases the slide 720 and enables the slide 720 totranslate along the arm 712. FIG. 62 demonstrates that the slide 720 caninclude a tooth or friction generator 722 that is contacts the arm 712until the slide 720 is compressed. When the slide 720 is compressedtoward the arm 712, a wall 724 of the slide 720 deflects away from thearm 712, which raises the tooth or friction generator 722 away from thearm 712 to facilitate movement of the slide 720 along the arm 712.

As illustrated in FIG. 61, the arm 712 can include markings or indiciato assist with determining the location of the slide 720 along thelength of the arm 712.

As discussed above, a non-stretching headgear generally indicates thatthe headgear should be set to a specific, customized size for each user.Preferably, the sizing is performed once and then is not changed duringsubsequent use. Using the break-fit assemblies described herein, thesizing can be temporarily adjusted for ease of donning the interfacewhile facilitating automatic reconnection of the headgear to thepredetermined size. As discussed above, the break-fit assembly can bepositioned on the mask (e.g., on the frame or on the seal), in-line byconnecting to one or more of the straps of the headgear, or in anotherportion of the headgear (e.g., along a seam in the back of theheadgear).

In some configurations, a component assembly can be provided to reducethe likelihood of accidental adjustment of a predetermined sizing of theheadgear. For example but without limitation, the component assembly canbe created to operate an adjustment mechanism only with deliberateinteraction. In one configuration, a key can be used to lock or unlockthe adjustment mechanism. By key, it is intended to have a broadinterpretation of a device that establishes control over the mechanism.The key could be a traditional key or could be another item. Forexample, the key could be a magnet or a magnetic component that attractsanother component to interact with an adjustment mechanism. By way ofanother example, the key could be a household item, such as ascrewdriver, pin, or the like. In one configuration, once the size hasbeen adjusted, a component can be removed to lock the adjustmentmechanism against inadvertent or undesirable resizing.

In some configurations, electronics can be added to improve the functionof the interface. For example, a strap or other component can have anincorporated track that acts as an electronic tape measure. When aninitial fitting of the interface is performed (e.g., by a sleeptechnician), the initial sizing can be bookmarked in an electroniccomponent of the interface. With each subsequent fitting or donning ofthe interface, the electronics can signal when the headgear is at theproper or predetermined size. For example, the user can stretch theinterface during donning and then tighten until the electronics indicatethat the predetermined length has been reached. Similarly, an actuatorcould be provided to automatically tighten the interface to thepredetermined size. The actuator could be a small motor, solenoid or thelike. The actuator could be integrated into the frame or the headgear,for example but without limitation. Furthermore, using the electronics,operating characteristics of a CPAP device could be monitored such thatan adjustment could be made to the headgear automatically to compensatefor leaks as soon as the leaks occur or are likely to occur.

While various embodiments have been described, it should be noted thatany of the adjustment mechanisms can be combined with any of thebreak-fit assemblies. In addition, the adjustment mechanisms can be usedwithout a break-fit assembly and the break-fit assemblies can be usedwithout an adjustment mechanism. Further, any interface (i.e., mask andheadgear) can be used with either or both of an adjustment mechanismdescribed herein and/or a break-fit assembly.

Although the present invention has been described in terms of a certainembodiment, other embodiments apparent to those of ordinary skill in theart also are within the scope of this invention. Thus, various changesand modifications may be made without departing from the spirit andscope of the invention. For instance, various components may berepositioned as desired. Moreover, not all of the features, aspects andadvantages are necessarily required to practice the present invention.Accordingly, the scope of the present invention is intended to bedefined only by the claims that follow.

1-18. (canceled)
 19. A mask and headgear system comprising a mask, themask comprising a frame and a seal supported by the frame, headgearconnected to the mask, and a break-fit assembly configured to elongateupon the application of a force exceeding a preselected force, the mask,headgear, and break-fit assembly together defining a loop that elongateswith forces that exceed the preselected force.
 20. The mask and headgearsystem of claim 19, wherein upon application of the force exceeding thepreselected force, the resulting elongation of the loop is sufficient toallow a user to don and position the mask on the user's head and face orto allow the user to remove the interface from the user's head and face.21. The mask and headgear system of claim 19, wherein the break-fitassembly resists elongation and remains connected in general use if aforce less than the preselected force is applied.
 22. A break-fitassembly for a mask and headgear assembly, the break-fit assemblycomprising a mechanical coupling that resists elongation from a firstlength to a second length until a force is applied that exceeds apredetermined force, the mechanical coupling comprising multiple partsand a stretch biasing member that connects two or more of the multipleparts.
 23. The break-fit assembly of claim 22, wherein the stretchbiasing member exhibits at least one of the following: (1) elasticcharacteristics and (2) spring characteristics.
 24. The break-fitassembly of claim 22, wherein the stretch biasing member provides aconnection between the parts of the mechanical coupling of the break-fitassembly.
 25. The break-fit assembly of claim 22, wherein the mechanicalcoupling requires a first force to disconnect and second force toreconnect, the second force being less than the first force.
 26. Abreak-fit assembly for a mask and headgear assembly, the break-fitassembly comprising a magnetic coupling that resists elongation from afirst length to a second length until a force is applied that exceeds apredetermined force, the magnetic coupling comprising multiple parts anda stretch portion.
 27. The break-fit assembly of claim 26, wherein themagnetic coupling fulfills a biasing function for the break-fitassembly.
 28. The break-fit assembly of claim 26, wherein the stretchportion provides a connection between two or more parts of the magneticcoupling.